The invention relates to a nontoxic, fabric-sparing cleaning agent with microbicidal action, particularly for textiles, and to its preparation and use.
Cleaning agents are usually compositions containing surface-active agents capable of solubilizing dirt in a solvent, particularly in an aqueous solvent. Because most dirt contains fats or has fat-like properties, it is removed with surface-active agents, particularly surfactants. In this manner, however, only fat-containing dirt can be solubilized. Other kinds of dirt such as, for example, proteins or protein-containing dirt, for example blood stains, colored substances, for example coffee or tea, and invisible dirt, particularly microorganisms, however, cannot be removed readily in this manner. For this reason, cleaning agents usually also contain at least one bleaching agent and/or at least one disinfectant, so that the remaining dirt is removed, at least in optical terms. After the removal of fatty and pigmented dirt, stains are usually removed oxidatively.
To this end, chlorine-releasing chemicals are often used which, because of their high oxidation potential, at the same time also act as disinfectants. Such oxidation, however, often destroys only the colored part of the stain, and the other insoluble substances remain contaminated with the base substance. Because of its high reactivity, however, chlorine bleach has the drawback of attacking colored textiles and in many cases changing their color or causing discoloration. Moreover, the aggressive chlorine bleach attacks the material to be cleaned, particularly textiles, so that after multiple washings their basic structure is destroyed, which reduces their strength.
For this reason, attempts have been made in the past to accomplish oxidative bleaching with peracetic acid. Although the acid, per se, exerts a sufficient disinfecting action, its penetration into porous materials is low, which particularly in the case of textiles results in insufficient sterilization. Moreover, like chlorine bleach, peracetic acid, which in cleaning agents is formed from perborates and cleaved-off acyl radicals, exerts an oxidative action although to a lower degree.
This oxidative action, although sufficient to exert the bleaching action that destroys colored stains and although gentler to many materials than are other bleaching agents, does not exert adequate disinfecting action in all cases. For example, aerobic spore-formers are not removed. Moreover, the use of per acids causes considerable damage to wool.
Finally, peroxide compounds react with proteinaceous dirt causing aging of the protein, particularly in the case of blood stains. Aged proteins, however, are removed more or less incompletely by cleaning agents when such agents are allowed to act for the usual length of time.
Hence, the object of the invention is to provide a cleaning agent which besides good cleaning properties exerts a sterilizing action, but in itself is not toxic.
Bioactive glasses have been known for a long time and have been described in summary form, for example, by Larry L. Hench and John. K. West in xe2x80x9cBiological Applications of Bioactive Glassesxe2x80x9d, Life Chemistry Reports 1996, vol. 13, pp. 187-241, or in xe2x80x9cAn Introduction to Bioceramicsxe2x80x9d, L. Hench and J. Wilson, eds., World Scientific, New Jersey (1993). Bioactive glasses, in contrast to conventional glasses, are characterized in that they are soluble in an aqueous medium and that they form a layer of hydroxyapatite on their surface. Most current bioactive glasses are prepared either as fusible glass, in which case they contain much less SiO2 and much more sodium than normal window or bottle glasses, or they are sol-gel glasses which then, in contrast to fusible glasses, contain a high amount of silicon dioxide and a small amount of sodium or no sodium at all.
The essential properties of bioactive glass are known to those skilled in the art and have been described, for example, in U.S. Pat. No. 5,074,916. Bioactive glass thus differs from conventional lime-sodium-silicate glasses in that it binds to living tissues.
Such bioactive glasses are used, for example, for healing damaged bones and particularly as synthetic bone transplants. Moreover, they are being used successfully in the healing of chronic wounds, particularly diabetic ulcers, as well as pressure sores and bed sores of elderly patients. For example, John E. Rectenwald, Sean Lee and Lyle L. Moldawer et al. (Infection and Immunity, submitted for publication) were able to show that in the mouse bioactive glass exerts an inflammatory [sicxe2x80x94xe2x80x9canti-inflammatoryxe2x80x9d seems to be meantxe2x80x94Translator] action brought about by stimulation of interleukin-6 (IL-6) activity and simultaneous inhibition of the inflammation-stimulating cytokines TNF-alpha, IL-1-alpha and IL-10 and of MPO (myeloperoxidase) (see also [Proceedings of the] 19th Annual Meeting, Surgical Infection Society 1999, Apr. 28-May 1, 1999).
Moreover, E. Allen et al. (Department of Microbiology and Periodontology, Eastman Dental Institute) reported that bioactive glass 45-S-5 obtainable from Bioglas(copyright), U,S. Biomaterials, Alachua, Fla. 32615, USA, exhibits antibacterial activity not shown by normal glass beads (window glass).
Such biologically active glasses, however, release considerable amounts of Ca2+ ions. Hence, it was to be expected that they would markedly increase the water hardness which would lead to increased calcium deposition and reduced cleaning action, so that they would not be suitable for use in detergents and cleaning agents.
Moreover, it was to be expected that the abrasive action of the glass particles would cause mechanical damage to materials and, in particular, would cause destruction of textile fabrics.
Surprisingly, we have now found that the afore-defined objective can be reached by means of a cleaning agent containing bioactive glass particles. Such particles preferably show a solubility higher than 250 xcexcg of alkali metal ions per gram of glass, the general expression xe2x80x9calkali metal ionsxe2x80x9d including alkaline earth metal ions.
Surprisingly, we have now found that a cleaning agent containing such glass particles not only acts as a biocide against viruses and bacteria, but is also gentle to the skin and to fabrics, causes no allergic reactions and, moreover, is capable of eliminating difficult-to-remove dirt such as aged proteins. Surprisingly, the release of alkali metal ions, and particularly alkaline earth metal ions such as Ca2+ and Mg2+, does not reduce the detersive action and also does not increase calcium deposition. Moreover, the added glass particles do not cause the feared destruction of or damage to the material to be cleaned, particularly textile fabrics.